Recently, a market size for IT outsourcing has grown. As internet technology has been developed for accessing information resources, information systems have become internet-based, which is called an ASP(Application Service Provider); evaluating the performance for ASP becomes important. Therefore, this paper attempts to investigate the salient characteristics of ASP. An ASP success model is proposed based on information systems success models found in the literature. Our model is tested through a survey from 291 small companies. LISREL is used to demonstrate the suitability of our model, and the success factors for ASP are also investigated. Our result is likely to help provide useful guidelines for the successful ASP implementations.